Decline In Prostate-specific Antigen Levels Research Articles

18F-fluorocholine positron emission tomography/computed tomography for early outcome prediction in metastatic castration-resistant prostate cancer patients treated with enzalutamide: A proof-of-principle study.

e16040 Background: We investigated the role of 18F-fluorocholine positron emission tomography/computed tomography (FCH-PET/CT) in the early treatment evaluation and outcome prediction in patients with metastatic castration-resistant prostate cancer (CRPC) treated with enzalutamide. Methods: Patients received enzalutamide daily after at least one chemotherapeutic regimen with docetaxel. Patients were evaluated monthly for serological prostate specific antigen (PSA) response and safety. FCH-PET/CT was done at baseline and was repeated after approximately 3 to 6 weeks. Univariate and multivariate Cox regression models addressed potential predictors of progression-free survival (PFS) and overall survival (OS). Results: Thirty-six patients, median age 72 years (range, 48-90 years) were treated with enzalutamide, whose 21 received one or more lines of therapy after docetaxel. Fourteen of 36 (36%) received previously abiraterone. A decline in PSA level of 50% or more was seen in 13 of 36 (36%) patients. Thirty-f...

Lenalidomide Monotherapy in Chemotherapy-Naive, Castration-Resistant Prostate Cancer Patients: Final Results of a Phase II Study

BackgroundWe investigated the activity of lenalidomide, which has antiangiogenic, antineoplastic, and immunomodulatory properties, in chemotherapy-naive, castration-resistant prostate cancer (CRPC) patients. PatientsPatients received 25 mg/d lenalidomide for 21 days in 28-day cycles, until disease progression or unacceptable toxicity developed. Endpoints included overall response rate and clinical benefit (overall response + stable disease), toxicity, time to radiographic progression, and time to prostate-specific antigen (PSA) progression, overall survival, and quality of life. ResultsThirty-two patients were enrolled in the study; of these, 77% (n = 25) had Gleason scores ≥ 7. The median age was 74 years (58-89 y), the median PSA level was 66 ng/mL (2-919 ng/mL), and 5 of 32 patients (17%) had liver or lung involvement. The median number of lenalidomide cycles was 3 (1-16 cycles). Stable disease was seen in 20 patients, for a clinical benefit rate of 63%. The median time to radiographic progression was 4 months (2-16 mo); the median overall survival was 20 months. Of 27 PSA-evaluable patients, 13 (48%) had a decline in PSA level; 3 (11%) had > 50% PSA decrease; the median time to PSA progression was 3 months (2-9 mo). Grade 3/4 hematologic toxicities were the most common adverse events without adverse impact on quality of life. Serious adverse events occurred in 14 patients (44%), including 1 patient (3%) with a rash definitely related to lenalidomide. ConclusionLenalidomide monotherapy demonstrates modest activity in chemotherapy-naive CRPC.

Sargramostim (GM-CSF) and lenalidomide in castration-resistant prostate cancer (CRPC): Results from a phase I-II clinical trial

BackgroundGranulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic cytokine that stimulates dendritic cells (DCs) and promotes uptake of tumor antigens by DCs leading to T-cell cross-priming. Lenalidomide (Revlimid) is an immunomodulatory analog of thalidomide with significant T-cell stimulatory and antiangiogenic properties. GM-CSF in combination with thalidomide induces prostate-specific antigen (PSA) responses in 20% to 25% of patients with castration-resistant prostate cancer (CRPC). In an effort to further evaluate the clinical and immune activity of GM-CSF and lenalidomide, we conducted a phase I-II trial in patients with CRPC. MethodsAsymptomatic patients with CRPC were enrolled. Prior immunotherapy or chemotherapy was not allowed. All the patients received 250μg of GM-CSF administered subcutaneously 3 times weekly along with 25mg/d of lenalidomide administered orally on days 1 to 21 of a 28-day cycle. The primary end points were objective, PSA response, and safety. Exploratory end points included activation of circulating DCs, regulatory T cells, and Th1 cytokine production. ResultsThirty-two patients were enrolled in the study. No dose-limiting toxicities occurred in the phase I portion of the study. Although 81% of the patients achieved a decline in the levels of PSA while on therapy, only 4 achieved a PSA level decline of≥50%. The overall response rate among 11 patients with response evaluation criteria in solid tumors-defined measurable disease was 18%. Overall toxicity was G1 and G2 in nature and included fatigue observed in 69% of the patients, nausea/vomiting in 34%, and diarrhea in 28% of the patients. Grade 3 or 4 toxicities occurred in 22% of the patients and were primarily thrombocytopenia (9%) or neutropenia (19%) or both. ConclusionsAdministration of GM-CSF and lenalidomide in patients with CRPC is safe with modest evidence of antitumor activity and no immune changes observed.

Neutropenia as a Potential Pharmacodynamic Marker for Docetaxel-Based Chemotherapy in Men With Metastatic Castration-Resistant Prostate Cancer

BackgroundDocetaxel clearance appears increased in men who are castrated. Neutropenia in cycle 1 may be a pharmacodynamic marker for docetaxel, which may enable tailored dosing in metastatic castration-resistant prostate cancer (mCRPC). Patients and MethodsThe association of cycle 1 neutropenia with overall survival (OS) was examined post hoc in a randomized phase II trial of 221 men with mCRPC who received docetaxel-prednisone combined with placebo or AT-101 (bcl-2 inhibitor); weekly blood cell counts were performed during the first cycle. Patients from both arms were combined because no outcome and toxicity differences were observed. OS was calculated from randomization by the Kaplan-Meier method, and Cox proportional hazards regression models were used to estimate the association with OS. ResultsThe difference in OS between men with day 8 ≥grade 3 neutropenia and those with ≤grade 2 neutropenia was significant after adjusting for trial stratification factors, pain, and performance status (hazard ratio [HR] 0.64; 2P = .048). Results were similar for logarithmic neutrophil counts adjusted for the risk group based on anemia, visceral metastasis, progression by bone scan and pain (HR 1.18; 2P = .07) for stratification factors (HR 1.20; 2P = .052) or both (HR, 1.20; 2P = .046). Men with ≥grade 3 neutropenia and ≥30% prostate-specific antigen level decline by day 90 had improved OS compared with men exhibiting neither (HR 0.51; 2P = .014). ConclusionsFor patients with mCRPC who received docetaxel, ≥grade 3 neutropenia on day 8 was prognostic for improved OS, which suggests its utility as a pharmacodynamic marker, in this hypothesis-generating analysis. Exploration of dose escalation of docetaxel to attain ≥grade 3 neutropenia on day 8 may be warranted.

Phase II trial of RAD001 and bicalutamide for castration‐resistant prostate cancer

Study Type--Therapy (cohort) Level of Evidence 2a. What's known on the subject? and What does the study add? Despite expanding treatment options for castration-resistant prostate cancer (CRPC), therapies with long response duration remain intangible due to prostate cancer cells' natural ability to develop iterative resistance. Androgen receptor (AR) signaling has been shown to play a critical role in CRPC and its expression is regulated by the PI3K-Akt pathway. Thus inhibition of AR signalling and PI3K-Akt-mTOR (a downstream mediator of the PI3K-Akt pathway) pathway is a logical combination in CRPC and we report a phase II trial of RAD001 and bicalutamide. Our study is the first clinical trial report of an AR inhibitor of PI3K-Akt-mTOR. The AR pathway and the PI3K-Akt-mTOR pathway are two of the most relevant growth pathway for CRPC. Despite low efficacy results from our trial there will be significant interest in the field for these data (dose, schedule, response, toxicity, trial design) as newer generations of both AR inhibitors and PI3K-Akt-mTOR inhibitors are in development and likely will be tested in combination in CRPC. • To determine best overall response and duration of response of RAD001, a selective inhibitor of mammalian target of rapamycin, in combination with bicalutamide in castration-resistant prostate cancer (CRPC). • To characterize the toxicity profile of RAD001 in combination with bicalutamide in patients with CRPC. • A phase II study was conducted to explore the efficacy and tolerability of RAD001 (10 mg daily) in combination with bicalutamide (50 mg daily) in men with progressive CRPC. • The primary endpoint was a composite of prostate-specific antigen (PSA) level and measurable disease response by standard criteria. • This single-stage trial with a sample size of 38 eligible patients provided 90% power to differentiate a response rate of ≥ 40% from a response rate of ≤ 20%, as expected for bicalutamide alone (α= 0.10, power = 0.90). • In total, 36 men were enrolled, with a median (range) age of 68 (60-72) years and median (range) baseline PSA level of 22.2 (8.4-121.3) ng/mL, and 89% had metastatic disease. • There were 31 (86%) patients had previously used bicalutamide for a median duration of 7.4 months. • There were two patients with a confirmed PSA level decline ≥ 50%. • The median (interquartile range) time to progression was 8.7 (7.9-15.9) weeks. • The most common toxicity was grade 1/2 mucositis, which was observed in 20 (56%) patients. • The combination of RAD001 and bicalutamide in men with CRPC was well tolerated but had low activity and failed to achieve the primary endpoint of improved response compared to the results previously achieved for bicalutamide alone in this population.

Phase II Study of Abiraterone Acetate in Chemotherapy-Naive Metastatic Castration-Resistant Prostate Cancer Displaying Bone Flare Discordant with Serologic Response

Abiraterone is an oral inhibitor of CYP17, which is essential for androgen biosynthesis. This multicenter study assessed its efficacy in patients with castration-resistant prostate cancer (CRPC), without prior chemotherapy or CYP17-targeted therapy, and frequency of bone scans discordant with prostate-specific antigen (PSA) and clinical response. Thirty-three patients received abiraterone acetate 1,000 mg daily with prednisone 5 mg twice daily in continuous 28-day cycles. Patients were evaluated monthly for efficacy and safety. Bone scan flare was defined as the combination, after 3 months of therapy, of an interpreting radiologist's report indicating "disease progression" in context of a 50% or more decline in PSA level, with scan improvement or stability 3 months later. A 50% or more decline in PSA level at week 12 was confirmed in 22 of 33 (67%) patients. Declines in PSA level of 50% or more were seen in 26 of 33 (79%) patients. Undetectable PSA levels (≤0.1 ng/mL) occurred in 2 patients. Median time on therapy and time to PSA progression were 63 weeks and 16.3 months, respectively. Twenty-three patients were evaluable for bone scan flare. Progression was indicated in radiologist's report in 12 of 23 (52%), and 11 of 12 subsequently showed improvement or stability. As prospectively defined, bone scan flare was observed in 11 of 23 (48%) evaluable patients or 11 of 33 (33%) enrolled patients. Adverse events were typically grade 1/2 and consistent with prior published abiraterone reports. Clinical responses to abiraterone plus prednisone were frequent and durable in men with metastatic CRPC. Further investigation is needed to clarify the confounding effect of bone scan flare on patient management and interpretation of results. Clin Cancer Res; 17(14); 4854-61. ©2011 AACR.

The illusion of prostate‐specific antigen decline in patients with metabolic syndrome and insulin resistance

What's known on the subject? and What does the study add? Studies have shown that PSA is negatively associated with obesity as a result of hemodilution or metabolic effect. Hemodilution could be the main reason for low PSA levels in obese men. However, the intrinsic metabolic effects such as insulin resistance (IR) or metabolic syndrome (MS) on PSA level have not been clearly evaluated although obesity is closely tied to MS and IR. We regarded MS and IR as the pathophysiological cornerstone of metabolic disorder in obesity and analyzed the relationships among MS, IR, and PSA levels, and plasma volume by using the concept of PSA mass, the total circulating PSA protein. PSA mass did not change depending on the severity of the obesity, MS or IR. Even the group with both MS and IR, which could be the most metabolically disturbed in this study, did not have different PSA mass, comparing with the group without any MS or IR. Thus, the decline in PSA level in men with MS or IR can be also explained by increased plasma volume other than any intrinsic metabolic effects. • To investigate the detailed mechanism of prostate-specific antigen (PSA) decline in metabolic syndrome (MS) and insulin resistance (IR), which lowers the predictive value of the PSA test, we examined the effect of haemodilution and the possibility of an intrinsic metabolic effect. • We analysed 28,315 men who underwent routine check-ups. We compared the age-adjusted mean PSA levels in subjects with and without MS before and after adjusting or stratifying the plasma volume. We analysed changes in PSA level, plasma volume and PSA mass according to obesity grade, number of MS components, IR severity and diagnosis of MS, IR or both using an analysis of covariance. • The PSA levels were lower in the group with MS than in the group without MS (P= 0.001), but this difference disappeared after adjusting or stratifying the plasma volume (P > 0.05 for all). The PSA levels decreased, plasma volume increased, and PSA mass did not change as the number of MS components increased (P= 0.002, P < 0.001, P= 0.55, respectively) or the IR severity increased (P= 0.001, P < 0.001, P= 0.34, respectively). • Similarly, PSA levels were lower, plasma volumes were higher and PSA masses were the same in subjects with MS (P= 0.002, P < 0.001, P= 0.10, respectively), IR (P= 0.018, P < 0.001, P= 0.94, respectively), or both (P= 0.003, P < 0.001, P= 0.86, respectively) than in subjects without those conditions. • The PSA decline in MS and IR may result simply from a haemodilution effect and be unrelated to intrinsic metabolic disturbances. For this reason, PSA levels could be underestimated in patients with MS or IR because of haemodilution.

Prognostic Significance of PSA, Gleason Score, Bone Metastases in Patients with Metastatic Prostate Cancer under Palliative Androgen Deprivation Treatment

Objective: The aim of this study was to evaluate the prognostic significance of each of the following in the development and progression of hormonal refractory disease in patients with metastatic prostate cancer under hormonal palliative treatment: The initial serum level prostate specific antigen (PSA), the Gleason score (GS), the presence of bone metastases with or without visceral metastases, and the PSA decline. Patients and Methods: During the time period from January 2005 to December 2008, a total of 92 patients with newly diagnosed, histologically confirmed metastatic prostate cancer (MPC) were under palliative androgen deprivation therapy. The age range was 52 to 85 years with a mean age of 66.2±7.9 years. MPC was diagnosed histologically after transrectal ultrasonography guided biopsy. The Gleason score assessment was determined by low power microscopic examination. Metastases were confirmed by positive bone scintigraphy with 925 MBq 99mTc-MDP using a tomographic gamma camera, computerized axial tomography or magnetic resonance imagining. Measurements of PSA levels were conducted by the radioimmunoassay method. The influences of the following prognostic factors were evaluated: The initial serum level of prostate specific antigen (PSA), the Gleason score (GS), the presence of bone metastases with or without visceral metastases, and the PSA decline, on the time to disease progression. Results: The time to progression was significantly delayed in patients with initial PSA level ≤50ng/ml (median: 32 months), Gleason Score ≤7 (median: 33 months), bone metastases only (median: 30 months) and PSA level normalization within 6 months (median: 30 months) compared to that of patients with initial PSA level >50ng/ml (median: 24 months), Gleason Score >7 (median: 24 months), bone, distant lymph nodes and/or visceral metastases (median: 24 months), PSA level decline (median: 18 months) (p-values were 0.002, <0.001, <0.001

Phase II study of paclitaxel and vinorelbine (Pacl‐Vin) in hormone‐refractory metastatic prostate cancer: double tubulin targeting

Androgen ablation is the standard treatment for advanced prostate cancer. However, most patients will eventually develop progressive hormone-refractory prostate cancer (HRPC). The aim of the Pacl-Vin study was to determine the efficacy and safety of paclitaxel in combination with vinorelbine in patients with HRPC, following from a phase I trial. Thirty castrate patients with progressive, metastatic prostate cancer were enrolled. Patients were treated with paclitaxel 40 mg/m2, vinorelbine 20 mg/m2 intravenously on day 1 and day 8 of a 21-day cycle. Two patients demonstrated a partial response and seven patients had stable disease from a cohort of 10 patients with measurable disease. Of 30 patients assessable for prostate-specific antigen (PSA) response, 19 showed stable disease, which was maintained for at least 4 weeks, while six (20%) experienced>or=50% decline in PSA levels. Median overall survival was 7.3 months (interquartile range (IQR): 4.7-9.9 months). Median progression-free survival was 3.3 months (IQR: 2.5-7.0 months). Improvement in quality of life measures was noted after three cycles of therapy. Grade 3 and 4 toxicities were: neutropenia 8%, febrile neutropenia 4%, infection 2%, anaemia 3%, lethargy 1% and somnolescence 1%. One patient died as a result of neutropenic sepsis. In a poor prognostic cohort of patients paclitaxel and vinorelbine is a tolerable regimen, with a 20% PSA and objective response rate. The majority of patients achieved PSA stability. Furthermore, quality of life parameters, such as pain, were improved. However, the low level of activity of this regimen precludes its further testing.

The Mechanism of Action of Estrogen in Castration-Resistant Prostate Cancer: Clues From Hormone Levels

Background Estrogen therapy plays a role in the management of castration-resistant prostate cancer (CRPC), although the mechanism of action is not fully known. This current analysis reports the relationship of change in adrenal androgen levels and prostate-specific antigen (PSA) response in patients with CRPC treated with estrogen therapy. Patients and Methods Hormone levels were measured for patients with CRPC treated in a multicenter phase II trial of 2 estrogen-containing compounds, the herbal supplement PC-SPES and diethylstilbestrol (DES), with known efficacy in CRPC. Patients with castrate levels of testosterone were randomized to initially receive either PC-SPES 960 mg t.i.d. or DES 3 mg/day. Levels of testosterone, dihydrotestosterone (DHT), estradiol, estrone, sex hormone–binding globulin (SHBG), dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEA-S), and androstenedione were obtained at baseline and at 12-week intervals until disease progression. Hormone levels were obtained for 38 patients, 20 treated with PC-SPES and 18 treated with DES. Results Significant declines between baseline and 12 weeks of treatment were observed in levels of serum testosterone ( P < .001), estrone ( P = .02), and DHEA ( P < .001). The percent changes at 12 weeks in these hormone levels were inversely proportional to baseline values as measured by Spearman's rank correlation (testosterone: −0.41, P = .01; estrone: −0.64, P = .0001; DHEA: −0.39, P = .02). Levels of SHBG increased in almost all of the patients (97%), with a median percent increase of > 5-fold ( P < .0001). Of the 38 evaluable patients, 15 (39% [95% CI, 24%–57%]) experienced a > 50% decline in PSA level. There was no significant difference between treatment groups or between responders and nonresponders in baseline distributions for any of the hormones. At follow-up, 73% of the responders had a decline in the level of DHEA-S compared with 41% of the nonresponders, resulting in a difference in the distribution of the percent change between the subsets (Mann-Whitney test: P = .03). Conversely, 64% of the responders compared with 30% of the nonresponders experienced an increase in DHT, with differing distributions of percent change ( P = .02). Conclusion Androgens decline in response to estrogen therapy. A decline in DHEA-S and a rise in DHT are both associated with a decline in PSA while patients receive estrogen therapy.

A phase II study of high‐dose calcitriol combined with mitoxantrone and prednisone for androgen‐independent prostate cancer

To evaluate the preliminary efficacy, safety, and impact on quality of life (QoL) of high-dose calcitriol (DN-101) combined with mitoxantrone and glucocorticoids in androgen-independent prostate cancer (AIPC). Nineteen patients with metastatic AIPC and no previous chemotherapy received DN-101 180 microg orally on day 1 and mitoxantrone 12 mg/m(2) intravenously on day 2 every 21 days with continuous daily prednisone 10 mg orally for a maximum of 12 cycles. A confirmed decline in prostate-specific antigen (PSA) levels by half was the primary endpoint. QoL was evaluated using the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire, and pain and analgesic use were evaluated. Five of 19 patients (26%; 95% confidence interval, CI, 9-51) achieved a >/=50% decline in PSA level. The median (95% CI) time to PSA progression was 16 (6-26) weeks. The overall median (95% CI) survival was 16 (6-26) months; 47 (21-73)% of patients achieved an analgesic response. Toxicity was similar to that expected with mitoxantrone and prednisone alone. The QoL analysis suggested a decrease in physical functioning and increase in fatigue, insomnia, and diarrhoea. DN-101 given every 3 weeks does not add significant activity to mitoxantrone and prednisone in AIPC, as measured by the PSA decline. The high rate of analgesic response is encouraging. The addition of DN-101 does not appear to increase the toxicity of mitoxantrone.

A Phase II Study of Estramustine, Docetaxel, and Exisulind in Patients with Hormone- Refractory Prostate Cancer: Results of Cancer and Leukemia Group B Trial 90004

Purpose Docetaxel/estramustine is a known active regimen in hormonerefractory prostate cancer (HRPC). A phase II study was conducted to assess the safety and efficacy of docetaxel/estramustine combined with exisulind, an apoptotic antineoplastic drug. Patients and Methods Eighty men with chemotherapy-naive HRPC were enrolled in a multicenter, cooperative group study. The treatment regimen consisted of oral estramustine (280 mg 3 times daily for 5 days), docetaxel 70 mg/m 2, oral exisulind (250 mg twice daily), oral dexamethasone (8 mg twice daily for 3 days), and oral warfarin (2 mg daily). Results Seventy-five eligible patients were treated with a median of 6 cycles of therapy. Fortyseven patients (62.7%; 95% CI, 50.7%-73.6%) had a ≤ 50% decline in prostate-specific antigen levels. Forty-six patients had measurable disease with 6 partial responses (13%; 95% CI, 4.9%-26.3%). The main grade 3/4 toxicities were neutrophils (79%), fatigue (15%), and thrombosis/embolism (10%). The median time to first progression was 5.1 months (95% CI, 4.4-6.3 months) and the median survival time was 17.8 months (95% CI, 14.7-20.1 months). Conclusion The combination of estramustine/docetaxel/exisulind was associated with significant thomboembolic toxicity despite prophylactic warfarin. The contribution of exisulind to toxicity is uncertain. Prostate-specific antigen decline, response rates, and progression-free and overall survival are similar to those reported with docetaxel/estramustine.

Multimodality treatment in hormone-refractory prostate cancer patients with bone metastases

Dear Sir, We agree with the interesting points made by Koutsikos et al. They confirm the feasibility of the combined use of bone-seeking radiopharmaceuticals and bisphosphonates and highlight the potential benefit of this combined treatment. We would like to stress the importance to study multimodality treatment strategies in well-designed clinical trials. These trials should evaluate the multidimensional character of pain, as well as survival, and they should incorporate imaging modalities for response stratification. Bone-seeking radiopharmaceuticals are indicated for the relief of bone pain in patients with multiple painful osteoblastic metastases. Several new approaches are being studied not only to improve treatment efficacy related to pain response but also to extend efficacy by improving overall survival. As a single treatment modality, treatment at short intervals has shown to be beneficial with regard to pain palliation and survival [1]. However, most progress has been made with combinations of treatment modalities, for example, bone-seeking radiopharmaceuticals and chemotherapy [2]. In a recent publication, we showed the feasibility of 153Sm-EDTMP combined with zoledronic acid in hormone-refractory prostate cancer patients [3]. The combination of these two phosphate-based pharmaceuticals does not lead to competition in uptake at the level of the calcified bone matrix, nor does it lead to unacceptable toxicity. As a phase I study, it was not designed to study efficacy. However, as an illustration of potentially increased efficacy, two patients showed a complete remission of pain and a remarkable decline in prostate-specific antigen levels over pretreatment values (−71% and −43%), and markers of bone metabolism (−65% and −90%) over a period of almost 6 months. These results suggest a clinical benefit. But, further research is needed to explore the possible benefit of bone-seeking radiopharmaceuticals in combination with bisphosphonates, preferably in phase II and phase III randomized controlled settings. In the past, our center performed a double-blind, placebo-controlled, randomized trial to study the efficacy of 186Re-HEDP compared to placebo [4]. Pain relief was assessed using an electronic diary containing questions reflecting the multidimensional character of pain. Daily pain assessment was mandatory because it fluctuated day by day. Besides a visual analog scale for pain and the assessment of daily activities, a medication index score was also registered. This complex method of evaluation showed a significant decrease of pain in the treated population. Besides this, the study illustrated the difficulty of pain response as an endpoint and the necessity of a well-designed method for pain evaluation. Although a survival benefit could not be detected in this study using 186Re-HEDP as a single modality treatment, survival should be studied in future trials focusing on the efficacy of bone-seeking radiopharmaceuticals in combination with bisphosphonates. Several clinicians have postulated the multimodality approach for the treatment of hormone-refractory prostate cancer patients with painful osseous metastases. Combinations of multiple single treatment modalities may lead to an improvement of clinical benefit beyond an additive effect alone. From all available single-agent modalities, docetaxel is currently the first choice because of its proven efficacy on patients’ survival [5]. Its toxicity is considerable, but responders show a clear benefit with regard to quality of life and survival. A combination of radiopharmaceuticals and chemotherapy might be an interesting therapeutical option. Besides the clinical benefit of each pharmaceutical separately, the radiation-sensitizing effect of chemotherapy may lead to synergy and a further improvement of clinical benefit. The combined use of chemotherapy as a radiosensitizer is well known in the field of external beam radiotherapy but must still be explored in the field of radionuclide therapy. Potential radiation modifiers may be docetaxel or other chemotherapeutics (such as platinum compounds or 5-FU). In hormone-refractory prostate cancer patients, continuous treatment with hormones and bisphosphonates in combination with periodical administrations of a bone-seeking radiopharmaceutical, modified by chemotherapy, may prove to be an effective regimen (Fig. 1). Such a regimen benefits from (1) the effects of repeated treatment with radiopharmaceuticals, bisphosphonates, and chemotherapy as single-agent modalities and (2) the radiation-sensitizing effects of chemotherapy. Different possible strategies should be studied in the future. Fig. 1 Proposed treatment regimen in hormone-refractory prostate cancer patients Last but not least, one of the greatest challenges in the field of nuclear oncology and oncology in general will be the selection of responders and nonresponders. Especially in hormone-refractory prostate cancer, a minority of treated patients show clinical benefit. It will prove to be beneficial to patients, as well as cost-effective, to recognize those who respond to the proposed treatment regimen. Molecular imaging may play a crucial role in identifying these subjects. In hormone-refractory prostate cancer patients, several tracers are being developed and studied for positron emission tomography imaging [6]. Stratification of patients and the development of new treatment strategies will lead to improvement of efficacy with improved overall survival.

A pilot dose‐escalation study of the effects of nordihydroguareacetic acid on hormone and prostate specific antigen levels in patients with relapsed prostate cancer

To assess the tolerability of the effects of nordihydroguareacetic acid (NDGA) and its effect on prostate-specific antigen (PSA) kinetics in patients with relapsed prostate cancer, as among the many biological effects of NDGA is the inhibition of the insulin-like growth factor 1 receptor (IGF-1R) tyrosine kinase. Eligible patients were those with an increasing PSA level after definitive local therapy, in either the non-castrate (androgen-dependent prostate cancer, ADPC) or the castrate state (castration-resistant prostate cancer, CRPC) with no evidence of metastatic disease by bone scan or computed tomography of the abdomen or pelvis. Treatment consisted of continuous oral daily dosing according to a planned dose escalation of 750, 1250, 1750, 2250 and 2500 mg of NDGA. PSA levels were measured every 28 days. Serial levels of testosterone, dihydrotestosterone, oestradiol and sex hormone-binding globulin were measured at baseline and monthly while on study therapy. Fifteen patients were enrolled, including 11 with ADPC and four with CRPC. There were asymptomatic increases in transaminase in six patients, two of which were grade 3, all occurring at >or=3 months. The increases in transaminase resolved after stopping NDGA but recurred with repeated dosing. Doses of NDGA up to 2500 mg/day caused no other toxicities. A median (range) of 5.5 (1-13) cycles were delivered. Of the 11 patients with ADPC, one had a decline in PSA level of >50% of the baseline value and one a decline of <50%. Three patients with ADPC had a greater than three-fold increase in PSA doubling time while on therapy, one from 11 to 46 months (750 mg), one from 9.5 to 49.5 months (1750 mg), and one from 5.9 to 46.2 months (2500 mg). There were no reductions in PSA level in patients with CRPC. There were no significant effects on levels of testosterone, dihydrotestosterone, oestradiol or sex hormone-binding globulin. Continuous daily dosing with NDGA is reasonably well tolerated but is associated with transaminitis in some patients, that occurs after several months on therapy. There were apparent effects on the rate of increase in PSA. Further study is required to determine the optimum pharmacokinetics and antitumour effects of this therapy.

Long‐term follow‐up of a neoadjuvant chemohormonal taxane‐based phase II trial before radical prostatectomy in patients with non‐metastatic high‐risk prostate cancer

To assess the feasibility and activity of a neoadjuvant treatment combining a luteinizing hormone-releasing hormone (LHRH)-analogue, estramustine and docetaxel before radical retropubic prostatectomy (RRP) in patients with high-risk prostate cancer. High-risk patients were defined as clinical stage > or =T3 and/or a prostate-specific antigen (PSA) level of > or =15 ng/mL, and/or biopsy a Gleason sum of > or =8. Patients received LHRH analogue treatment until the PSA nadir (a stable PSA level for two consecutive determinations) and then, continuing hormone therapy, a combined regimen of estramustine and docetaxel. Patients had RRP within a month of completing the neoadjuvant regimen. All patients were assessed for toxicity and surgical complications. A clinical response was defined as complete (CR, the disappearance of all palpable and radiological abnormalities and a decline in PSA level of > or =90%) or partial (PR, a decline in PSA level of half or more with stable or improved palpable and/or radiological abnormalities). A pathological response was defined as 'complete' (undetectable cancer), 'substantial' (residual cancer in < or =10% of the surgical specimen) or 'minimal' (residual cancer in >10% of the surgical specimen). The biomarkers p53, bcl-2, MIB1, erbB2 and factor VIII were also evaluated. Of 22 patients enrolled between March 1999 and January 2002, 21 (mean age 63 years; mean PSA level 61 ng/mL; median biopsy Gleason sum 8) completed the neoadjuvant therapy. The clinical stage was organ-confined in three patients (15%); five (25%) had pelvic lymphadenopathy on computed tomography. The neoadjuvant treatment was well tolerated, with only one grade 2 toxicity (Eastern Cooperative Oncology Group grading). All PSA values decreased by >90% from baseline after hormonal therapy only, and the mean reduction from before to after chemotherapy was statistically significant (P = 0.001). Three patients (15%) had a CR, 16 (80%) had a PR and one (5%), with sarcomatoid tumour, had progression; 19 had non-nerve-sparing RRP and there were no major complications during or after RRP. The pathological assessment showed that one patient (5%) had no tumour (pT0) and six (32%) had a 'substantial' response. The overall rate of organ-confined disease was 58%, vs a mean 8% predicted likelihood from the Kattan nomogram. Five patients (26%) had positive surgical margins and four (21%) had positive lymph nodes. At a median follow-up of 53 months, eight patients (42%) were disease-free. Organ-confined disease (P = 0.022), residual cancer at pathology in < or =10% of the surgical specimen (P = 0.007) and no seminal vesicle invasion (P = 0.001) correlated with disease-free survival. A neoadjuvant chemohormonal regimen before RRP is feasible and active in patients with high-risk prostate cancer. The rate of pathological organ-confined disease was higher than expected and responding patients had an 85% disease-free survival rate at 5 years.

Phase I/II Study of Bortezomib Plus Docetaxel in Patients with Advanced Androgen-Independent Prostate Cancer

To determine the dose-limiting toxicities and maximum tolerated dose, and evaluate the antitumor activity of bortezomib/docetaxel combination therapy in androgen-independent prostate cancer. Two bortezomib doses (1.3 and 1.6 mg/m(2)/dose) in combination with four docetaxel doses (25-40 mg/m(2)/dose) were evaluated. Both drugs were administered weekly for 2 out of 3 weeks. Antitumor activity was evaluated using prostate-specific antigen (PSA) levels and Response Evaluation Criteria in Solid Tumors guidelines. Eighty-three patients received at least one dose of study drug. No dose-limiting toxicities were observed despite escalation to the highest dose level. PSA response (>or=50% decline in PSA levels from the baseline) occurred in 19 (28%) of 67 evaluable patients and was maintained for >or=4 weeks in 14 patients (21%). According to Response Evaluation Criteria in Solid Tumors guidelines, 11% achieved a partial response, and an additional 67% had stable disease. The degree of proteasome inhibition was similar to that reported with single-agent bortezomib. Treatment was well tolerated; fatigue was the most common drug-related adverse event, whereas diarrhea was the most common drug-related grade 3/4 adverse event. No clinically significant febrile neutropenia or neuropathy occurred. The maximum tolerated dose of this 21-day regimen has not been reached. The highest dose level (1.6 mg/m(2) bortezomib plus 40 mg/m(2) docetaxel) was feasible and tolerable; bortezomib plus docetaxel showed antitumor activity. Activity and tolerability results were consistent with previous studies of bortezomib alone or in combination with docetaxel. Further investigations are warranted to determine activity and optimize bortezomib/docetaxel therapy in androgen-independent prostate cancers.

Preliminary evidence that the allogeneic response might trigger antitumour immunity in patients with advanced prostate cancer

To explore the possibility that allogeneic responses might, by chance, encompass cross-reactive T cell clones specific for neo-antigenic tumour determinants, and thereby activate antitumour immunity; such cross-reactions are well documented for antiviral immunity, and genetic instability in developing cancers generates many neo-antigenic determinants as potential targets for immune responses, but the biology inevitably favours tumour progression. Fourteen patients with hormone-refractory prostate cancer received full-thickness skin allografts from different, unrelated donors (fellow patients) until each had received six grafts. Serum prostate-specific antigen (PSA) level was used as a surrogate for tumour mass. One patient had a remarkable decline in PSA level, with levels at 1 year lower than before grafting. A second patient had stable PSA levels for almost 2 years. A third patient had stable PSA levels for 10-12 months before they resumed an exponential rise. Of four patients with PSA levels of > 10 ng/mL, three required surgery or radiotherapy for obstructive symptoms during or shortly after grafting. Transplant rejection involves mechanistically atypical T cell recognition of allogeneic major histocompatibility complex antigens, with massive polyclonal T cell activation. This unique aspect of T cell biology might represent a novel approach for initiating cross-reactive antitumour responses.

A phase II evaluation of imatinib mesylate (G) in stage M0 prostate cancer (PC) patients (pts) on hormonal therapy (HT) with evidence of biochemical relapse

14612 Background: Imatinib mesylate (Gleevec, G) is a potent inhibitor of the tyrosine kinases and other signaling mediated events. Preclinical models suggest that G inhibits platelet derived growth factor (PDGF) and stem cell factor (SCF) which are important for prostate cancer growth. This trial was designed to evaluate the safety and efficacy of G in PCA pts on HT with stage M0 disease. Methods: Eligible PCA pts included: stage M0 disease with rising PSA levels while on hormonal therapy, no prior chemotherapy. Planned treatment included G 400 mg PO BID given up to a maximum of 12 months. The statistical endpoint for this trial was the% of pts with a ↓ in prostate specific antigen (PSA) ≥ 50% lasting ≥ 4 wks. A 2 stage trial was designed where the study would terminate if the% of pts meeting the endpoint was not convincingly &gt; 30% with 5% chance for error. Pts with a &gt; 50% rise in PSA from baseline were removed from study. Follow-up included monthly toxicities and PSA (specimens frozen/stored until completion of each 3 months of therapy). Results: From 10/1/02–10/11/04, nine pts were enrolled. Pt characteristics included median: age of 67 years (range 52–80), ECOG performance status of 0 (range 0–1), baseline PSA of 29.6 ng/ml (range 2.69–39.52), # prior hormonal manipulations of 3 (1–5). Prior local therapies included: 1 status post (s/p) RP alone, 2 s/p RT alone, 2 s/p neoadjuvant HT plus RP, 2 s/p neoadjuvant HT plus RT. Two pts had no prior local therapy. Two pts had prior salvage RT, 1 had prior palliative RT. Eight of 9 pts evaluable for response and toxicity. One patient never received treatment. None of the pts had a decline 50% decline in PSA level lasting ≥ 4 weeks. Three of 8 pts (38%) had rapid increases in PSA and 4/8 pts (50%) developed metastatic disease after 3 months of therapy. Only one pt completed 12 months of planned therapy. Grade 3/4 toxicities included: fatigue (25%), rash (25%), arthralgias (12.5%), peripheral edema (25%), depression (12.5%), necessitating dose delays and/or discontinuation of G in 4/8 pts (50%). Conclusions: These data suggest significant toxicity and low clinical benefit. Further evaluation of Gleevec in this pt population is not warranted. No significant financial relationships to disclose.

Deferred combined androgen blockade therapy using bicalutamide in patients with hormone‐refractory prostate cancer during androgen deprivation monotherapy

To assess the effect of adding bicalutamide on serum prostate-specific antigen (PSA) levels in patients with hormone-refractory prostate cancer (HRPC) during androgen deprivation monotherapy (ADMT). Forty-four patients with HRPC were treated with deferred combined androgen blockade (CAB) therapy, administering bicalutamide 80 mg once daily. HRPC was defined biochemically as three consecutive rises in PSA level during ADMT. The treatment response was defined as a > or = 50% decline in PSA levels. Prognostic values of various pretreatment variables for responsiveness to deferred CAB were determined statistically. When the disease relapsed during deferred CAB, bicalutamide was discontinued and the patients were evaluated for the antiandrogen withdrawal syndrome (AWS). Of the 44 patients, 29 (66%) had a PSA response; the median PSA failure-free survival was 9.2+ months. Biopsy Gleason score was the only pretreatment variable predictive of a PSA response (mean Gleason score 7.9 in responders and 8.7 in nonresponders). The PSA doubling time (PSA-DT) was the only statistically significant variable of PSA failure-free survival in a multivariate analysis. The 1- and 2-year PSA failure-free survival rates were 43% and 31% in patients with a PSA-DT of >4 months, while it was 21% and none, respectively, in those with a PSA-DT of <4 months. Responders to deferred CAB had a statistically longer cancer-specific survival than nonresponders. None of 20 patients who were evaluated for AWS had the condition. Deferred CAB therapy using bicalutamide is effective in patients with progression during ADMT, particularly in those with lower Gleason score tumours or a longer PSA-DT. AWS after deferred CAB is uncommon.

Antiandrogen withdrawal alone or in combination with ketoconazole in androgen-independent prostate cancer patients: A phase III trial (CALGB 9583). Small EJ, Halabi S, Dawson NA, Stadler WM, Rini BI, Picus J, Gable P, Torti FM, Kaplan E, Vogelzang NJ, UCSF Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA.: J Clin Oncol 2004;22:1025–33

Antiandrogen withdrawal (AAWD) results in a prostate-specific antigen (PSA) response (decline in PSA level of ≥50%) in 15% to 30% of androgen-independent prostate cancer (AiPCa) patients. Thereafter, adrenal androgen ablation with agents such as ketoconazole (K) is commonly utilized. The therapeutic effect of AAWD alone was compared with simultaneous AAWD and K therapy. AiPCa patients were randomized to undergo AAWD alone ( n = 132), or together with K (400 mg orally [po] tid) and hydrocortisone (30 mg po each morning, 10 mg po each evening; n = 128). Patients who developed progressive disease after AAWD alone were eligible for deferred treatment with K. Eleven percent of patients undergoing AAWD alone had a PSA response, compared to 27% of patients who underwent AAWD and simultaneous K ( P = .0002). Objective responses were observed in 2% of patients treated with AAWD alone compared to 20% in patients treated with AAWD/K ( P = .02). There was no difference in survival. PSA and objective responses were observed in 32% and 7%, respectively, of patients receiving deferred K, and were more common in patients with prior AAWD response. Treatment with K was well tolerated, and resulted in a decline in adrenal androgen levels, which rose at the time of disease progression. K has modest activity in AiPCa patients, while AAWD alone has minimal activity. Adrenal androgen levels fall with treatment with K and then climb at the time of progression, suggesting that progressive disease while on K may be due to tachyphylaxis to the adrenolytic properties of K.